Physiographic regions of the United States in the context of Geography of the United States

Nevin Melancthon Fenneman (26 December 1865 – 4 July 1945) was an American professor of geology, with a long career at the University of Cincinnati. His contributions were primarily in the large scale geographical understanding of American geology and based on his wide ranging studies, he produced a classification of US physiographic regions using a three-tiered system of 8 major divisions, 25 provinces and 78 sections that remains in use today.

The Atlantic Plain is one of eight distinct physiographic divisions of the contiguous United States. Using the USGS physiographic classification system, the Atlantic Plain division comprises two provinces and six sections. The Coastal Plain province is differentiated from the Continental Shelf province simply based on the portion of the land mass above and below sea level.

The lands adjacent to the Atlantic coastline are made up of sandy beaches, marshlands, bays, and barrier islands. It is the flattest of the U.S. physiographic divisions and stretches over 2,200 miles (3,500 km) in length from Cape Cod to the Mexican border and southward an additional 1,000 miles (1,600 km) to the Yucatán Peninsula. The central and southern Atlantic Coast is characterized by barrier and drowned valley coasts. The coastal Atlantic plain features nearly continuous barriers interrupted by inlets, large embayments with drowned river valleys, and extensive wetlands and marshes. The Atlantic plain slopes gently seaward from the inland highlands in a series of terraces. This gentle slope continues far into the Atlantic and Gulf of Mexico, forming the continental shelf. The relief at the land-sea interface is so low that the boundary between them is often blurry and indistinct, especially along stretches of the Louisiana bayous and the Florida Everglades.

The Blue Ridge Mountains are a physiographic province of the larger Appalachian Highlands range. The mountain range is located in the Eastern United States and extends 550 miles (885 km) southwest from southern Pennsylvania through Maryland, West Virginia, Virginia, North Carolina, South Carolina, Tennessee, and Georgia. The province consists of northern and southern physiographic regions, which divide near the Roanoke River gap. To the west of the Blue Ridge, between it and the bulk of the Appalachians, lies the Great Appalachian Valley, bordered on the west by the Ridge and Valley province of the Appalachian range.

The Blue Ridge Mountains are known for having a bluish color when seen from a distance. Trees put the "blue" in Blue Ridge, from the isoprene released into the atmosphere. This contributes to the characteristic haze on the mountains and their perceived color.

The Appalachian Highlands is one of eight government-defined physiographic divisions of the contiguous United States. It links with the Appalachian Uplands in Canada to make up the Appalachian Mountains. The Highlands includes seven physiographic provinces, which is the second level in the physiographic classification system in the United States. At the next level of physiographic classification, called section/subsection, there are 20 unique land areas with one of the provinces having no sections.

The Appalachian Highlands are characterized by a diverse physiographic division.